1. Field
The present disclosure relates to sodium manganese composite oxides and electrodes and sodium secondary batteries including the same.
2. Description of the Related Art
As mobile electronic devices such as video cameras, mobile phones, and laptop computers have become lightweight and highly functional, research is being conducted into high capacity and high energy density batteries that may be used as power supplies for driving such devices.
Lithium batteries have energy densities that are three times as high as those of lead-acid batteries, nickel-cadmium batteries, nickel metal hydride batteries, nickel-zinc batteries, or the like, and may be rapidly charged and thus, the lithium batteries are commonly used for commercial purposes.
However, the lithium batteries have stability problems due to highly reactive lithium and the element lithium is expensive. Thus there remains a need for improved battery technology.